Defined in rt_sys.h, this function writes a character to the console. The console might have been redirected. You can use this function as a last resort error handling routine.


void __ttywrch(int ch);


The default implementation of this function uses semihosting.

You can redefine this function, or __raise(), even if there is no other input/output. For example, it might write an error message to a log kept in nonvolatile memory.

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ARM C and C++ Libraries and Floating-Point Support User Guide:

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